ABSTRACT
The upgrade of sustainable resource waste into a valuable and beneficial material is an urgent task. The current paper outlines the development of an economical, sustainable, and prolonged adsorbent derived from Sargassum siliquastrum biomass and its use for potent 2,4-dichlorophenoxyacetic acid (2,4-D) removal. A simple carbonization approach was applied to obtain the highly functionalized carbon structure, which was subsequently transformed into a novel magnetic nanoadsorbent. The magnetic nanoadsorbent was characterized using Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Brunauer Emmett Teller (BET)-specific surface area, and vibrating sample magnetometer (VSM). The characterization results confirm the successful formation of a high specific surface area and a uniform distribution of Fe3O4/NiS NPs grafted activated carbon. The adsorption kinetics was more accurately described via the pseudo-second order model; nevertheless, the isothermal data showed that the Langmuir model was most suitable. The monolayer adsorption capacity for 2,4-D was 208.26 ± 15.75 mg/g at 328 K. The favourability and spontaneity of the adsorption process were demonstrated by thermodynamic studies. The adsorbent displayed exceptional selectivity for 2,4-D and high stability in multi-cycle use. Electrostatic attraction, π-π stacking, and hydrogen bonding were all believed to have an impact on the sorbent's robust 2,4-D adsorption. Analyses of real tap and Nile River water samples showed little effect of the sample matrix on 2,4-D adsorption. This study presents an innovative approach for developing highly efficient adsorbent from natural biomass and offers an affordable way to recycle algal waste into beneficial materials.
Subject(s)
Herbicides , Nanotubes , Sargassum , Water Pollutants, Chemical , Adsorption , Charcoal/chemistry , Magnetic Phenomena , 2,4-Dichlorophenoxyacetic Acid , Kinetics , Water Pollutants, Chemical/chemistry , Spectroscopy, Fourier Transform Infrared , Hydrogen-Ion ConcentrationABSTRACT
In this work, we investigated the impact of the concentration on the spectral and amplified spontaneous emission spectra (ASE) of a conducting polymer of poly(2,5-di(3,7-dimethyloctyloxy) cyanoterephthalylidene) (PDDCP) in tetrahydrofuran (THF). The findings demonstrate that the absorption spectra exhibited two peaks at 330 and 445 nm across the concentration range (1-100 µg/mL). Irrespective of the optical density, altering the concentrations did not affect the absorption spectrum. Also, the analysis indicated that the polymer did not agglomerate in the ground state for any of the concentrations mentioned. However, changes in the polymer had a substantial effect on its photoluminescence spectrum (PL), likely due to the formation of exciplexes and excimers. Also, the energy band gap also varied as a function of concentration. At a certain concentration (25 µg/mL) and pump pulse energy (3 mJ), PDDCP produced a superradiant ASE peak at 565 nm with a remarkably narrow full width at half maximum (FWHM). These findings can provide insight into the optical characteristics of PDDCP, which may have potential applications in the fabrication of tunable solid-state laser rods, Schottky diodes, and solar cell applications.
Subject(s)
Lasers , PolymersABSTRACT
This paper reports the structures, morphologies, optical properties, and photoconversion efficiency (η%) of the In2S3/ZnO core-shell heterostructures nanorod arrays (IZCSHNRAs) produced via the controlled successive ionic layer absorption and reaction (SILAR) cycles. As-produced samples were characterized using XRD, FESEM, TEM, UV-Vis, PL, XPS and FTIR techniques. The proposed IZCSHNRAs revealed nearly double photocurrent density and η% values compared to the pure ZnO nanorod arrays (ZNRAs). In addition, the light absorption, crystallinity and microstructures of the specimens were appreciably improved with the increase of the SILAR cycles. The deposited nanoparticles of In2S3 (ISNPs) on the ZNRAs surface was responsible for the improvement in the heterostructures, light absorption and photogenerated electron-hole pairs separation, thus enhancing the photoconversion performance. It is established that a simple SILAR approach can be very useful to produce good quality IZCSHNRAs-based photoelectrodes required for the future development of high performance photoelectrochemical cells (PECs).
ABSTRACT
In this research, nanocomposite solid polymer electrolytes (NCSPEs) comprising methylcellulose/pectin (MC/PC) blend as host polymer, ammonium chloride (NH4Cl) as an ion source, and zinc oxide nanoparticles (ZnO NPs) as nanofillers were synthesized via a solution cast methodology. Techniques such as Fourier transform infrared (FTIR), electrical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) were employed to characterize the electrolyte. FTIR confirmed that the polymers, NH4Cl salt, and ZnO nanofiller interact with one another appreciably. EIS demonstrated the feasibility of achieving a conductivity of 3.13 × 10-4 Scm-1 for the optimum electrolyte at room temperature. Using the dielectric formalism technique, the dielectric properties, energy modulus, and relaxation time of NH4Cl in MC/PC/NH4Cl and MC/PC/NH4Cl/ZnO systems were determined. The contribution of chain dynamics and ion mobility was acknowledged by the presence of a peak in the imaginary portion of the modulus study. The LSV measurement yielded 4.55 V for the comparatively highest conductivity NCSPE.
ABSTRACT
Zinc oxide nanoparticles (ZnO NPs) were biosynthesized. According to gas chromatography/mass spectrometry analysis, chalcone, the main phytochemical, is probably complexed with Zn ions that are then oxidized to ZnO NPs by atmospheric O2 during heating. The ZnO NPs were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and Brunauer-Emmett-Teller surface area analysis. Sphere-like ZnO NPs were formed with 11 nm mean crystallite size, 5.2 m2 g-1 surface area, and 0.02 cm3 g-1 total pore volume. The synthesized ZnO showed excellent photocatalytic degradation (96.5±0.24% in 1 hour at 25 °C) of malachite green (MG) in aqueous solutions under ultraviolet light at optimum conditions; pH 10, MG initial concentration of 20 mg L-1, and ZnO dose of 1.5 g L-1. Also, ZnO showed very good reusability (92.9± 0.2% after five runs). The experimental data obeyed pseudo-first-order kinetics (R2 = 0.92). The photocatalysis process was dependent on the following species in the order: OH. > electron/positive hole pairs > O2.-. Moreover, photodegradation efficiency decreased in the presence of CO32-, HCO3-, and Cl-, but increased in the presence of NO3- and SO42- ions. Thus, the green synthesized ZnO NPs can be applied as an efficient photocatalyst for the removal of MG from aqueous media.
Subject(s)
Nanoparticles , Zinc Oxide , Catalysis , Phytochemicals , Rosaniline Dyes , WaterABSTRACT
Background and objectives: Research on suicidal behaviors during pregnancy in Egypt is limited; being apparently rationalized by pregnancy is a protective period. This study aimed to address the current suicide risk (CSR), and evaluate its correlates of among pregnant women in Egypt.MethodsIt is a cross-sectional study which included 835 of Egyptian pregnant women who were receiving their antenatal care at Zagazig University Obstetrics and Gynecology Outpatient clinics, during the period from 1 October 2017 to 30 September 2018. The sociodemographic and clinical data were collected by a simple semi-structured questionnaire. The psychometric assessment included Beck Suicidal Ideation Scale (BSS), Zagazig Depression Scale (ZDS), Hamilton Anxiety Rating Scale (HAM-A), and Structured Clinical Interview for DSM-IV-TR Axis II Personality Disorders (SCID-II) for assessment of CSR, and comorbid depression, anxiety and personality disorders, respectively.ResultsAmong pregnant women, 23.4% reported CSR. This included suicidal ideation of 21.6% and suicidal attempt of 1.8%. Predictors of CSR were history of intimate partner violence (IPV) exposure (OR 8.8, 95% CI: 2.8, 27.7), identification of their current pregnancy as a female baby (OR 6.9, 95% CI: 2.0, 23.5), previous history of fetal loss (OR 3.9, 95% CI: 1.5, 10.6), and moderate-to-severe depression (OR 3.0, 95% CI: 1.0, 8.7).ConclusionsOur findings suggest that CSR, including suicidal ideation and attempts, is not rare during pregnancy. Exposure to IPV is the most robust predictor of CSR. Pregnant women should be routinely screened for suicidal behaviors, violence exposure and depressive symptoms, as part of their antenatal assessments. (AU)
Subject(s)
Humans , Female , Pregnancy , Suicide , Pregnant Women , Gender-Based Violence , Obstetrics , Gynecology , EgyptABSTRACT
INTRODUCTION: Type 2 diabetes mellitus (T2DM) is a well-recognised risk factor for cardiovascular disease and the prevalence of atrial fibrillation (AF) is higher among patients with T2DM. Direct current cardioversion (DCCV) is an important management option in persistent AF. We sought to determine independent risk factors for immediate and short-term outcomes of DCCV for treatment of AF in patients with T2DM. METHODS: Retrospective outcome analysis of DCCV for persistent AF in 102 T2DM patients compared with 102 controls. RESULTS: DCCV was successful in 68 (66.6%) people with T2DM compared to 86 (84.3%) in the control group (P = 0.003). After initial successful cardioversion, only 38 (37.2%) T2DM patients remained in sinus rhythm compared to 63 (61.8%) in the control group (P = 0.007) at a median follow-up of 74.5 days (IQR 69.4-77.4). Multiple logistic regression analysis showed that the presence of T2DM (P = 0.014), digoxin use (P = 0.01), statin use (P = 0.005), left-atrial size (P = 0.01), and LV ejection fraction (P = 0.008) were independent risk factors for immediate DCCV failure. T2DM (P = 0.034) was an independent risk factor for AF relapse. Among patients with T2DM, previous DCCV (P = 0.033), digoxin use (P = 0.035), left-atrial size (P = 0.01), LV ejection fraction (P = 0.036), and HbA1c (P = 0.011) predicted immediate failure of DCCV whilst digoxin use (P = 0.026) was an independent risk factor for relapse of AF. CONCLUSION: T2DM, higher HbA1c, digoxin treatment, and structural and functional cardiac abnormalities are independent risk factors for immediate DCCV failure and AF relapse.